1. Field of the Invention
The present general inventive concept relates to an image forming apparatus, and more particularly, to an image forming apparatus which improves developer supply configuration.
2. Description of the Related Art
An electrophotograhic image forming apparatus forms an image on a printing medium through charging, exposing, developing, transferring and fixing processes. The electrophotograhic image forming apparatus includes a laser printer, a photocopier, a multifunction printer, etc.
As illustrated in FIG. 1, one of the developer supply methods of a conventional image forming apparatus includes an integrated type where a developer storage part 8 storing a developer T and a developing part 3 developing a printing medium are integrally provided inside a casing 2. The other developer supply method of the conventional image forming apparatus includes a separate type where a developer storage tank 10 and a developing unit 20 are separated from each other, as illustrated in FIG. 2.
In the case of the integrated type, a plurality of agitators 9a and 9b are provided in the developer storage part 8 to prevent the developer T from being clotted and to supply the developer T to a supplying roller 7 provided therebelow. The supplying roller 7 frictionally charges the developer T and supplies it to a developing roller 5. A doctor blade 6 controls the thickness of the developer T attached to a surface of the developing roller 5, thereby developing an electrostatic latent image of a photosensitive drum 4.
In the case of the separate type, the developer T stored in the developer storage tank 10 is supplied to the developing unit 20 through a developer supplying pipe 30. An agitator 13 is provided in the developer storage tank 10 to move the developer T to the developer supplying pipe 30.
The developer T moves along the developer supplying pipe 30 and is supplied to a developer receiver 23 of the developing unit 20. Then, the developer T is supplied from the developer receiver 23 to a supplying roller 26 within a unit casing 21 by the agitator 13 which rotates along a rotating axis thereof. The supplying roller 26 frictionally charges the supplied developer T and supplies it to a developing roller 27.
However, in the conventional separate type developer supplying method, if a user does not print for a long period of time, the developer T becomes adhered to the developer supplying pipe 30, and thus is not smoothly supplied to the developing unit 20. Then, image density becomes non-uniform, and printing quality is lowered.